Public health agencies around the world have renewed efforts to increase the incidence and duration of breastfeeding. Maternity leave mandates present an economic policy that could help achieve these goals. We study their efficacy, focusing on a significant increase in maternity leave mandates in Canada. We find very large increases in mothers' time away from work post-birth and in the attainment of critical breastfeeding duration thresholds. We also look for impacts of the reform on self-reported indicators of maternal and child health captured in our data. For most indicators we find no effect.